EMONTX_SHIELD - Need help to configure sketch - ESP Easy Mega

Hardware emonTx
21

No, that is your a.c. adapter. The ADC is the Analogue to Digital Converter inside the ATMega328P processor on your Wemos.

60.606 is the number you must change. You wrote earlier:

Therefore, my first guess for the correct value there is 60.606 × 1500 ÷ 750 = 121.212

Correct. The number 253.755 is correct - you said the voltage reading is correct. Do not change this.
The number 1.7 is the one you must change to get the phase calibration correct.

Not unless you send your a.c. adapter to me and I measure it. I have measured the UK version - but the EU version is different. 1.7 might be correct, but it might not be. It is only a “best fit” number - it corrects for three separate things, two of which vary according to the voltage and current being measured.

22

ESPEASY is software or more correctly, firmware.

Ref:

https://espeasy.readthedocs.io/en/latest/

image
image560×536 23.6 KB

23

ho ok,

i thing that i just need to put 60.606 because the calc is : (100A/0.05A)/33Ohms but i need to caluibrate this number too.

ok, i check that :slight_smile:

thanks.

Cnopix

24

That is only true for the emonTx Shield and a genuine Arduino Uno. If your ESPEASY reports the wrong hardware type, or the ADC reference voltage is not 5 V, or a combination of these things, then it is another number inside emonLib that is wrong, which is causing the error. That number is the result of this calculation inside emonLib:

((SupplyVoltage/1000.0) / (ADC_COUNTS))

And if either SupplyVoltage or ADC_COUNTS are wrongly detected, then your calibration is wrong. The rest of the calculation to give I_RATIO is

  double I_RATIO = ICAL *((SupplyVoltage/1000.0) / (ADC_COUNTS));

ICAL is your 60.606 number, so you can see that changing that achieves the same result as correcting either SupplyVoltage or ADC_COUNTS. V_RATIO comes from a very similar calculation, and your power is

realPower = V_RATIO * I_RATIO * sumP / numberOfSamples;
25

it’s seems to be better now :slight_smile:

i need to in a few days if it’s correct or not :wink:

Thaks for your help Robert.

Cnopix.

26

You cannot expect the theoretical values to give you an exact value, all components are subject to manufacturing tolerances (the c.t. and a.c. adapter are ±3% each), then there are all the components in the Shield, and the Wemos itself.

27

hey Robert,

it’s working great since a lot of days :slight_smile:

i have just one issue on my phase1. when i don’t use any power, i see that the amout of wats is negatif (between -30 and -35W).

Do you have an idea about this issue ?

i test a new calibration,i change the Clamp with phase 2 or 3 but same result.

Br,

Cnopix

28

Is this when the c.t. is taken off its cable, or when it is on the cable but no current is flowing?

It is not unusual to see a small current - 35 W ≡ 160 mA - and this is with the emonTx Shield that can measure up to 100 A - it is almost certainly due to electrical noise, either coming from your 5 V power supply, or generated within the Wemos itself. If you have another 5 V power supply, it is worth trying that. Alternatively, some users have found that using the 7 - 12 V d.c. input is better, if you have a power supply that is suitable - ideally NOT a switched-mode - you could also try that.

29

it’s when no current is flowing.

it’s happened on all clamp if i put all on the same cable.

i check if i have another power supply to check :wink:

Br,

Cnopix

30

That seems to indicate that it’s either a problem with that analogue input to your Wemos, or that cable is picking up (or carrying) interference.